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burlmart's avatar
burlmart
Explorer
Mar 08, 2015

help w/ coach battery USE/STORE toggle acting up

after leaving shore power on for 18 hours to run a small space heater and charge batteries overnite a couple nites back (lightish freeze to 26 deg), i unplugged shore and disconnected the coach batt using the use/store toggle like i do often.

today i went to exercise genset, so i toggle the disconnect switch to USE, primed the genset to 15 clicks, toggle genset switch in at top to start, and after turning a few times, it stopped, and there was no more DC power to coach. this has never happened.

so then i plugged in to shore power and toggle to USE, and as normal, toggle light goes from pale to dark red. again had coach juice and genset primed some more clicks. then i unplug shore and genset turns over once and stops, and again, no DC power. i notice toggle red lite is now stuck on pale red no matter how you toggle it - this is the color it has when shore power is on but you do not want to charge batteries and you toggle off to STORE. lite is normally blank if no shore power and toggled to STORE.

so next i crank up engine, toggle to USE turn over genset and it starts up fine. after engine is warm turn it off and run genset with some loads for a while. i see w/ voltmeter that coach batt is not charging (12.66V), but chassis is (over 14V). with the BiRD relay on this rig, both batts always charge whenever there is shore or genny AC on.

shut off genset and plug in shore with USE toggled and again, only chassis batt is charging (over 13V). at rest, both batts are 12.66V coach and 12.74V chassis. with disconnect switch still toggled to USE with dark red lite, when i turn on 3 hallway lights and within 5 secs we hear the disconnect solenoid thump off and no more lights and toggle lite is now stuck at pale red.

repear previous step but turn on half as many hallway lites, and it takes a good three times longer before once more, thump goes the disconnect solenoid.

is this typical of bad solenoid, or might i have a blown fuse from the 18 hours of running heater and battery charging from a 50' extension cord 15 amp shore line? (i have done this many times before w/ no issues.)

two solenoids, some two prong fuses, and maybe the BiRD relay are in a box under the rig by the coach batt.

i can never know if i give TMI to diagnose or what, but i need electrical savvy help here, for sure.

6 Replies

  • NEWS

    for anyone googling this in future, all i said in OP is what was happening EXCEPT there does not appear to be a pale and a bright red, or i could not see it this morning as i repeated all same symptoms as i reported yesterday. i cannot see well and in afternoon light i may have fooled myself and martha. in better overcast morning, i only saw brite (i had called it dark in OP) red.

    loose battery ground connection it was!!

    i thank you guys and am amazed you saw that so readily. i was so sure it was a bad solenoid i asked snowman for detailed info based on a previous solenoid event.

    i learned a lesson today about checking connections. working from y'all's advice i discovered my coach batt strapdown had enough slack to work a bit loose from a somewhat stiff ground cable.

    thanks, thanks, thanks!
  • Try southernkilowatt's suggestion first. Clean the connections to the coach batteries and make sure they are good and tight. That is simple and quick and if may very well solve the problem.
  • Also, at some point (after I crashed the step into something because it was not powered when I started the engine) I moved the step wire onto a different terminal. I don't recall if the drawing shows the old or new placement of the wire. It shouldn't matter to your situation.

    The thing labeled Batt Switch is the Use/Off switch.
  • From what you describe, it sounds to me like a bad or weak connection. I would start at the batteries, clean all connections you can see and give everything a good once over look. I suspect a faulty ground connection.
    Good Luck
    SK